Underreamer



Nw. 7, 1939. `w. B. DUNLAP, JR

Filed April 16', 1958 3 sheets-sheet 1 v Sheets-Sheet 2 W. B. DUNLAP, JR

UNDERREAMER Filed April 16, 1938 Nov. 7, 1939.

Nov. 7, 1939. w. B. DUNLAP, .JR

UNDERREAMER Filed April 16, 1958 3 Sheets-Sheet 5 Paten-ted Nov; -7, 1:939

UNDEBBEAMER k Wcyman B. Dunlap, Jr., Corpus Christi, Tex., as-

signor to Delta Foundation Company, Inc., a

corporation of Texas t Application April 16, 1938, Serial No. 202,443

-9 claims. '(01. s55-74) The invention relates to under-reamers of the type which is employed in under-reaming shallow holes for piling, foundation supports, and the like.

Oneuse to which the invention may be put is the under-reaming of holes drilled to receive the piles or foundation supports of building structures. Ithas become more or less customary in drilling holes to receive cement foundation posts to under-ream the lower end of the hole after it has been dug so as to increase the width of the base upon which the weight is supported.

It is an object .of this invention to provide an under-reamer for enlarging the lower ends of holes of this character which will operate positively and accurately to enlarge the opening to the desired extent.

I desire to provide an under-reamer having lat.. erally expanding blades and to provide mechanism whereby the blades may be uniformly expanded in a lateral direction so as to cut a at bottom hole.

It is a further object of the invention to provide a cutting blade uponan under-reamer for this purposewhich will move the cuttings from the blades toward the interior where they may be received within the bucket.

.It is a further objectoi the invention to so form the bucket in'connection with the expanding blades that when the tool is removed from the hole the earth cuttings in the bucket may be readily dumped so that the tool may be ready for use.

The invention resides largely in the particular construction and arrangement of the parts which make up my improved under-reamer and for a better understanding thereof reference is made to the accompanying drawings.

In Fig. lv is a central longitudinal section through my improved device, certain parts being shown in elevation.

Fig. 2 is a similar side view taken at right'angles to the view shown in Fig. l and with parts broken awayalong the central longitudinal section.

Fig. v3 is a side view similar to the Fig. 1 view but with the blades shown in expanded position.

Fig. 4 is a top plan view of the device.

Fig. 5 is a transverse section on the plane 5 5 of Fig. l.

Fig. 6 is a bottomV plan view of the device.

Fig. 7 is an assembly View showing the device as employed in under-reaming.

The body of .the housing for my device is formed as a cylindrical bucket i of heavy sheet y the hook 8' with the staple d. This will be understood from Fig. 1.

metal. The lower end of this bucket is formed with an approximately disc-shaped closure plate 2, which is hinged at 3 to a. stationary portion of the bottom. This structure will be under-- stood best fromFig. 6. On the inner side of the 5 closure plate 2 and opposite the hinge 3 is an upwardly extending staple 4 to engage with a The' latch rod 5 is pivoted toward the upper endv of the bucket at 6. This pivot pin is mounted i0 up'ona block, l secured to the side wall of the bucket. The latch rod 5 extends above the pivot and has an upper handle B whereby the rod may be moved laterally so as to' engage or disengage l5 Centrally of the bottom closure plate is a' supporting lug or boss 9, which projects a short distance below the plate and acts as a support on which the bucket may be rotated. On each side of the supporting post are openings I0, at the rearward sides of which are, mounted cutting blades il. These blades extend but a short distance below the plate and act merely to scrape up and scoop into the lower end of the bucket such cuttings as may be found upon the bottom of the hole.

Thecutters comprise two cutting blades l2. These blades, as shown particularly in Fig. 2, are spaced apart relative to the axis of the bucket and one blade is adapted to move laterally through a slotted opening I3 in the side of the bucket while the other blade extends laterally from the opposite side through a similar' slot I3 in the bucket.

With reference particularly to Fig. 2, it will be seen that there are two spaced plates for each of the blades. There is an outer plate ifi and an inner plate l5 between which each blade I2 lis .ward from the drive stem or kelly i9 through 43 openings in the blades I2 and thus form driving members through which a downward thrust on the blades may be accomplished.

. The Vdrive stem or kelly iSis preferably polygonal in cross section so that it may be engaged for :oignon by any appropriate device at the surface. The shaft'l upon which the blades l2 are supported extends centrally through the lower end of the kelly and it will be seen that a downthe 'blades i2 downwardly.

In their downward movement the blades are guided by means of pins working in cam slots in the blade. There is an upper cam slot in each blade through which a pin 2i extends. Said pin 2i is extended through the lower ends of the spaced plates I4 and I5 and is held in a stationary position while the blades are being moved. The slotsrzll are curved in a proper direction so as `'to force the blade in its downward movement in a lateral direction at the lower end.

There is a second pin 22 on the opposite side of the blade and at a point spaced upwardly from the lower end of the blade. This pin is supported in a cross plate 2l in the housing. As will be seen from Fig. 5, the cross plate 23 is spaced at one side of the center of the bucket and in proper position adjacent the outer face of the cutting blade I2. Said pin 22 is formed on the inner end of a stud 32 which is screwed through the supporting plate 23 and fits within a cam slot 24 in the blade. As will be noted this cam slot is formed approximately on the arc oi a circle and extends in the opposite direction from the slot 20 at vthe upper end of the blade.

. The lower ends of each of the blades are inclined upwardly and rearwardly from the forward cutting edge 25. This sloping lower edge 26 of the blade is formed at such an angle that when the blades are properly expanded the sloping edge will be lying in position engaging with the bottom of the hole. On the forward side of each oi' the cutting blades is formed a cutting orV `scrap-- ing member 21. This cutting member extends in the direction of rotation of the tool and serves to engagethe side of the hole with a scraping and cutting action which moves the material toward the interior of the bucket. There is a lower blade indicated in dotted lines in Fig. 2 at 28, which cuts along the bottom ci the hole and also serves to retain the 'material so that it may be moved toward the interior of the bucket.

In'the operation of my device the blades will be in contrasted position fitting within the bucket,

as shown in Fig. l. When ahole has been drilled, as shown in Fig. 7, at 29, my device may be lowered to the bottom of the "hole so that the supporting post 8 will rest uponthe bottom and servel as a center about which the' bucket may be rotated. The drive stem i! may be engaged by any appropriate mechanism at the surface and rotated with Vthe usual righthand rotation, as viewed from the upper end. As the bucket is rotated a downward thrust will be exerted upon the drive stem i9 tending to push the blades directly downward. In this downwardl movement of the blades an expanding torce will .be exerted due to the pins 2i and 22 engaging within the cam slots 20 and 24, respectively, in the blades to force the lower end of the blade radially outward. The rotation o! the tool will bring these blades into cutting L utact with the sideoi the hole and the material willbe gradually-reamed away -from the bottom as the-blades are progressively advanced outwardly. When the blades have been advanced to such an extent that the pins 2l and v22 engage in the upper ends of the cam slots in which they are moving, the hole will be fully enlarged. The vextent to which the blades can be moved, will, of course, be regulated by the size of the blades and the' length of the cam slots. In removing the tool an upward pull on the kelly will withdraw the blades to the Fig. I positionL Y 2,178,859 ward thrust upon the drive stem Il will move thx-ugh the engagement of the pins in the cam slo v It will be noted in the movement of the blades that the lower cutting end 25 will be moved outwardly so as to cut a at bottom hole. This lower cutting end does not move in the arc of a circle but is thrust straight out so that when the underreaming has been finished they will lie as shown e in Fig. 7 with the lower edge 26 in a horizontal direction so that the bottom ofthe hole will be also horizontal. It wm be seen that the material scraped away from the side wall of the hole in enlarging the opening will be moved inwardly into the bucket so that the bucket may be pulled upwardly out o i' the hole to remove cuttings at any time, and it may be of advantage at some time during the under-reaming operation to empty the y of the latch vrod 5. 'I'here maybe a spring, as

shown at 30 in Fig.. 4, to hold the latch rodl in latched position but the movement ofthe upper end' of the rod or lever will unlatch the lower closure in such form as to allow the contents to be readily removed at any time. What is claimed as new is:

1. A device for under-reaming holes, compris-l.l

ing a cylindrical bucket, a pair of oiiset outwardly extensible cutting vblades therein, slotted open ings in said bucket to allow movement therethrough oi' said blades, a drive shaft pivotally connected with the upper ends of said blades.

'transverse pins mounted on said bucket and engaging throughfcan'i slots -in each of said blades.

said slots being curved whereby the downward movement o! said blades relative to said pins by said drive shaft will cause the lower ends oi said blades to be moved outwardly against the wall of the hole.

2. A device for under-reaming holes, comprising a cylindrical bucket, a pair of offset outwardly extensible cutting blades therein, slottedcpen# ings in said'bucket to allow movement therethrough of said blades, a drive shaft pivotally connected with the upper ends of said blades. upper and lower cam slots in said blades, pins fixedV in'said bucket extending through each oi' said slots, said slots being so curved that when said blades are moved downwardly by said drive shaft, the lower ends of said blades will be moved outwardly in a horizontal direction.

3. In a device voi! the character described, a cylindrical bucket, a pair of reaming blades normally housed therein, but adapted to be projected through slots in said bucket, lateral plates slidably supporting the upper ends of each of said blades, pins in said plates extending through cam slots in said blades, cam`slots in said blades adjacent the lower endsthereof, pins Supported in said bucket and extending through said last mentioned slots, and means to move said blades 'downwardly and simultaneously rotate said bucket. j 4. In a device of cylindricalbucket, a pair of reaminar blades normally housed therein but adapted to be projected through slots in said bucket, lateral plates slidthe character described, a`

abLv supporting the upper ends of each of said v blades, pins in said plates extending through cam slots in said blades, means to move the lower ends of said blades laterally as they are moved downwardly, anda drive shaft pivotally connected A of, a downwardly presented boss 'on said plate to support said bucket as it is rotated, means to latch said closure plate, a pair of laterally movable reaming blades in said bucket, a drive shaft secured to said blades to communicate a downward thrust thereto, and stationary means in said bucket engaging each of said blades to deflect the lower end of each blade outwardly in an approinmately radial direction as the bucket is rotated.

6. In a device of the character described, a bucket, a closure plate for the lower end thereof, a downwardly presented boss on said plate to support said bucket as it is rotated, means to latch said closure plate, a pair of laterally movable reaming blades in said bucket, a drive shaft secured to said blades to communicate a downward thrust thereto, and means associated with said bucketand engaging with cam surfaces adjacent both ends of said blades to cause the lower end of each blade to be moved horizontally outwardly as said shaft is moved downwardly and rotated.

7. In adevice of the character describeda bucket, a closure plate for the lower end thereof, a downwardly presented boss on said plate to support said bucket as it is rotated, means.

to latch said closure plate,`a pair of laterally movable reaming blades in said bucket, a drive shaft secured to said bladesl to communicate a downward thrust thereto, stationary means in said bucket engaging each ofI said blades to deflect the lower -end of each blade outwardly in an approximately radial direction as the bucket is rotated, and forwardly extending scraping means on the outer and lower edges of said blades to scrape the 'bottom -and side walls of a bore hole.

8. In an runder-reamer, a bucket having cutter receiving slots therein, a closure plate for the lower end of said bucket, a manually operable .latch to retain said platelin closed position,

means on said plate to rotatably support said bucket, a drive shaft, blades pivoted thereto at their upper ends, and stationary means on said bucket to engage said blades and move the lower ends radially outward as said blades are forced downwardly by said shaft.

9. In a device of the character described, a cylindrical bucket, a pair of reaming bladesnormallyhoused therein but adapted to be projected through slots in opposite sides of said bucket,

lateral plates slidably supporting the upper ends of each of said blades, means associated with said bucket and engaging said blades, responsive to the downward movement of saidblades to direct the movement of the upper ends of said blades laterally relative to the axis of said bucket, separate means to move the lower ends of' said blades laterally as they are moved do-wn-- wardly, and a drive shaft pivotally connected with the upper ends of said blades to move said blades downwardly and simultaneously rotate said bucket.

WEYMAN B. DUNLAP, Jn. 

